A transportation network for vehicles can include several interconnected main routes on which separate vehicles travel between locations. Some of the main line routes may be single routes, which means that only a single vehicle can travel along the single main line route in a given direction and two vehicles traveling in opposite directions cannot simultaneously travel across the same section of the single main line route. For example, rail vehicles such as trains may travel along a main line track but may be unable to simultaneously travel in opposite directions along the same section of the main line track. However, vehicles traveling at different speeds may need to travel along the same section of the main line route in the same direction. In order to avoid a faster vehicle overtaking and colliding with a slower vehicle moving ahead of the faster vehicle, a siding section of the route may be connected with the main line route.
A siding section of the route may include a section of the route that is connected with the main line route and provides an auxiliary path for one of the vehicles to pull off the main line route so that another vehicle can pass along the main line route. For example, a slower moving first train travelling on a main line track can pull off of the main line track onto a siding section of track while a second train travelling in the same direction on the main line track can continue along the main line track and pass the first train on the siding section. This event between two vehicles traveling in the same direction can be referred to as a “pass event.” The first vehicle can be referred to as a “leading” vehicle as the first vehicle leads the second vehicle along the main line route. The second vehicle can be referred to as an “overtaking” vehicle as the second vehicle passes and overtakes the first vehicle. Once the overtaking vehicle passes the leading vehicle, the leading vehicle may pull back onto the main line route and proceed behind the overtaking vehicle.
The vehicles may move within the transportation network according to various schedules. The schedules may dictate times that the vehicles are expected to arrive at various locations. However, due to various anticipated or unforeseen circumstances, one or more of the vehicles may be running behind schedule. For example, trains may be behind schedule due to damaged portions of the track, unexpected delays in leaving one or more scheduled locations, and the like.
The pass events can be included in the schedules of the vehicles. If one of the vehicles that participate in a pass event is behind schedule and arrives late to the pass event, then the other vehicle in the pass event may need to stop and wait. For example, if the overtaking train for a pass event between trains is behind schedule, then the leading train may continue to the originally scheduled meet event and wait an additional time period for the late overtaking train to arrive and pass on the main line track. As another example, if the overtaking vehicle is traveling faster than the leading vehicle such that the overtaking vehicle may reach the leading vehicle before the pass event, the overtaking vehicle may be forced to abruptly slow down significantly in response to warning signals disposed along the route of the vehicles that indicate warnings to the overtaking vehicle to avoid colliding with the leading vehicle. The abrupt slowing down can be wasteful of fuel compared to a gradual slowing down of the overtaking vehicle.
A need exists for a system and method for modifying movement plans or schedules of vehicles that reduce pass events that result in wasted fuel.